A user interface of a television is usually constructed by buttons provided on a housing of the television or devices such as a remote control in conjunction with an on-screen display (OSD) represented on a monitor of the television. More specifically, in an OSD, certain texts or graphics are generated and displayed on the monitor via an OSD controller so that the user obtains messages from the television. For example, when the user switches channels, or adjusts the volume or display quality with the aid of the buttons on the housing or via the remote control, the OSD controller shows information associated with the above user actions by displaying texts and graphics at appropriate positions on the monitor, so as to facilitate the user to complete adjusting and controlling various values and functions of the television as well as providing information of different programs.
Referring to FIGS. 1A and 1B showing schematic diagrams of OSD, when the user presses a menu button 110 on a remote control 11, apart from displaying an image of a television program, a monitor 100 of a television 10 also displays a first function menu 121 as shown in FIG. 1A. However, along with the ever-growing functionality of television, the first function menu 121 no longer accommodates all function options, such that the monitor 100 also displays a second function menu 122 as shown in FIG. 1B when the user presses a change-page button 111 on the remote control 11. During the switching from the first function menu 121 to the second function menu 122, direct image replacement is generally adopted by the prior art, which does not attend to any visual effects during the switching. Further, since the OSD controller in the television supports only common two-dimensional image processing, sophisticated visual effects that can leave the user with an impression are also rather difficult to achieve. Therefore, it is an object of the invention to improve the above shortcomings of the prior art.